What does Gardner Denver shutdown 128 high discharge temp mean?
Short answer: High airend discharge temperature shutdown. If your Gardner Denver AirSmart controller is showing SHUTDOWN #128 HIGH DISCH TEMP, the controller has logged a specific, documented condition. This page covers what it means, what causes it, what you can safely fix yourself, and when — and why — it takes a technician.
What exactly is the machine telling you?
Temperature at the airend discharge exceeded 240°F (116°C) and the controller stopped the compressor to prevent damage. This is one of the most common shutdowns on rotary screw machines.
Which machines show this?
Gardner Denver rotary screw compressors fitted with the first-generation AirSmart microprocessor controller — a wide range of oil-injected packages, including VFD-equipped variable-speed units where the controller supervises the drive. The first-generation AirSmart reports problems as numbered codes: SHUTDOWN #1xx and #2xx faults that stop the machine, and ADVISORY #3xx warnings that let it keep running while flagging maintenance. That numbering matters when you search — the later AirSmart G2 dropped the numbers and displays plain-text fault names instead, so a numbered code on the screen tells you that you are on the earlier controller. Shutdowns clear with Stop/Reset once the machine has stopped; advisories acknowledge with the Enter key.
What causes it?
- Oil level low at the sight glass — less oil means less heat carried away from the airend
- Oil cooler faces packed with dust and lint
- Hot intake air from a badly ventilated room driving discharge temperature past 240°F
- Thermal valve or oil system fault that keeps cooling oil from circulating properly (the repeat case)
Can you fix it yourself?
Usually, yes — this is the most common rotary-screw shutdown, and cooling, cleaning, and topping up oil clears most of them. If it trips again after that, stop restarting it.
Step by step — what to try, in order:
- Let the machine cool fully, then check the oil level at the sight glass
- Clean the oil cooler faces of dust, lint, and debris with the machine off
- Improve room ventilation — hot intake air drives discharge temperature up
- Press Stop/Reset to clear the fault and restart while watching the temperature
When do you need a technician — and why?
A machine that keeps hitting 240°F despite good oil and clean coolers has a thermal valve or oil-circuit fault, and diagnosing that means opening the pressurized oil system with the right instruments.
If it does come to a service call and you're in Nashville, TN or Birmingham, AL, we maintain independently compiled lists of local companies that service industrial air compressors — real businesses with verified contact information, none of whom paid to be listed.
Related questions
What does SHUTDOWN #128 HIGH DISCH TEMP mean on a Gardner Denver AirSmart controller?
High airend discharge temperature shutdown. Temperature at the airend discharge exceeded 240°F (116°C) and the controller stopped the compressor to prevent damage. This is one of the most common shutdowns on rotary screw machines.
Can I fix SHUTDOWN #128 HIGH DISCH TEMP on a Gardner Denver AirSmart controller myself?
Usually, yes — this is the most common rotary-screw shutdown, and cooling, cleaning, and topping up oil clears most of them. If it trips again after that, stop restarting it.
When does SHUTDOWN #128 HIGH DISCH TEMP on a Gardner Denver AirSmart controller need a technician?
A machine that keeps hitting 240°F despite good oil and clean coolers has a thermal valve or oil-circuit fault, and diagnosing that means opening the pressurized oil system with the right instruments. Call a technician if the shutdown repeats after cooling, cleaning, and oil-level checks — thermal valve or oil system faults need professional service.
Verified against service documentation: Gardner Denver AirSmart controller documentation for SHUTDOWN #128 HIGH DISCH TEMP (best-aire.com)